Westmeath simply couldn’t deal with the devastating inside-forward line of Flynn, Chris Healy and Ben McCormack and with Con Kavanagh also chipping in with three points from wing-forward, this result never really looked in doubt.
Kildare started in blistering fashion with seven unanswered points inside the opening 16 minutes.
Westmeath though were given a way back into the game from their first score when Jack Quinn toe-poked home a goal in the 18th minute following a goalmouth scramble.
That helped them cut the Kildare lead to 0-9 to 1-2 by the half-time break but Kildare simply outclassed them in the second half.
Healy and Flynn ran rampant and Flynn rounded off the win with a successful late penalty after he had been fouled by Anthony McGivney.
Bryan Murphy’s team march on to the final and in this sort of form will take some stopping, no matter who comes through on the other side of the last four.
Dublin and Laois meet in Parnell Park on Saturday to decide the other finalist.
N Flynn 1-5 (1-0 pen, 4 frees); B McCormack 0-4, C Kavanagh, C Healy 0-3 each; C McMonagle 0-1
J Quinn 1-0; R Hickey (f), D Giles (f), P Fagan 0-1 each.
D Campbell; E Bateman, D Maguire, P Mescal, R Houlihan, S Ryan, B Byrne; L Flynn, P Connell; C Hartley, B Kelly, C Kavanagh, B McCormack, C Healy, N Flynn.
C McMonagle for Kelly, M Hyland for Bateman, 39; R Feely for Hartley, 46; J Flynn for Houlihan, 59; J Costello for Byrne, 59; C Delahunty for McCormack, 60.
K Fagan; R Wallace, I Ilunga, L Sayeh, G Murray, A McCormack, S Duncan; G Delaney, T Watts; S Corcoran, R Hickey 0-1f, D Conway, D Giles 0-1f, J Quinn 1-0, P Fagan 0-1.
A McGivney for Wallace, 18; M Monaghan for Giles, 38; R Cunningham for Murray, 45; J Halligan for Corcoran, 50; N Mitchell for Watts, 51.
S Murphy (Louth).